Lock



y 1933. M. c. MAXWELL ET AL 1,906,701

LOCK

Filed Dec. 4, 1931 m l \I IN VENTORS fiyjxzbm ATTORNEY range th Patented May 2, 1933 UNITED STATES PATENT OFFICE MAXWELL C. MAXWELL AND FRANK E. THOMPSON,

or sramronn, CONNECTICUT,

ASSIGNORS TO THE YALE & TOWNE MANUFACTURING COMPANY, OF STAMFORD,

commorlcur.

LOCK

Application filed December 4', 1931. Serial No. 578,994.

This invention relates to anti-pick locks, and more especially to means for preventing the picking of cylinder plugs and particularly those of the sliding tumbler type. An object of our invention relates to the arrangement of a shutter adapted to operate in the keyway of a sliding tumbler plug, and to be actuated by a key in that plug, so that unless the proper keyis utilized, it will be impossible to set the tumblers and rotate the plug in a conventional manner.

'It is a further object of our invention to so design the shutter and the keyway cooperating therewith, that it will be relatively impossible to manipulatea picking tool in the keyway of the lu without forcing the shutter into a dea locking position relatively to the plug and cylinder.-

It is a further object of our invention to design a plug adapted for a key having parallel offset portions, and to preferably aron par of the plug and is abnormally enla ged in another part of the plug, there being a shutter in the enlarged keyway determininglmem' er and adapted to limit the shape of t serted into the lock to a key having the aforesaid ofl'set parallel leg portions. It is a still.

further ob ect of the lnvention to arrange the shutter of our plug so that it will cooperate with a considerable portion of the face.

of the key to determine the cross section of the key' which is required for the plug.

Referring now to the drawing wherein a modification of our invention is shown, Fig. 1 shows a key adapted forthe particu ar plug which we prefer to utilize. trates front and side views of a cylinder lock showing the application of our invention. Fig. 3 shows parts of the cylinder constituting our invention in the order in which they are assembled. Fig. 4 is a sectional view of the plug and cylinder with the tumblers Fig. 5 is a section along the lines 5-5 of Fig. 4, while Fig. 6 is a section along the linesG-G of Fig. 4.

Referring now more particularly to the drawin and especially Fig. 4, it will be noted t at we employ a plug 10 having a keyway so that it is of normal size in ortion acting. as a e key which may be in-.

Fig. 2 illusshaped or manipulated tool or key, the por keyway 11 through the major portion thereof, and a series 0 tumbler chambers 12 leading into the keyway and having tumblers therein adapted to be actuated by a key in a manner well known to those skilled in the art. Each of the tumblers is spring'pressed by a spring 13 in an upward locking direction so that its head portion 14 looks into a groove 15. Preferably, the heads of the turn blers are shaped as shown in the form of a T, and cooperate with similarly formed complementary slots in the main cylinder slot 15, so that surreptitious rotation for picking purposes will interlock the tumblers securely to the cylinder.

The keyway 11 is of normal size for cooperation with the key of Fig. 1, but is enlarged at the front of the plug, so as to form a relatively wide portion 16. Preferably, the front end of the plug is formed by cooperation of an insert section 17 adapted to fit onto a cutaway portion 18 of the plug,

for a shutter 21 and a spring 20,

the key until the hole 23 inthe key comes op posite that bit. While-the key.is in contact with bit 22, it will force a leg portion 28 of the shutter into a cooperating slot 29 in the cylinder. Similarly, if any other portion of t e shutter is contacted by an improperly tion 28 will be moved into the slot 29 .to interlock the plug and cylinder. This acts to maintain the plug and cylinder against relative rotary movement during the insertion of the key and makes for easy key action because the tumblers do not ride hard against the walls of slot 15 as is the case when the key is inserted with an incidental sli ing of the plug. It also prevents t e application of the rotary torque to the plug re- 'quired to assist in the usefof a picking tool ht turnother than one shaped like the key. As will be indicated later, the shutter functions also to prevent the use of a picking tool even if shaped like the key'of Fig. 1. Once the key has been fully inserted, the hole 23 will correspond to the bit 22, and the legportion 28 will be out of the slot 29, so that if the tumblers have been properly positioned, the plug will now be free for rotation relatively to the cylinder.

As will be quite apparent, the operation of the shutter in cooperation with the enlarged portion 16 of the keyway, acts to so limlt the longitudinal shape of the keyway as viewed in Fig. 2 that it is necessary to use the offset key shown in Fig. 1. The key will properly be inserted against the bits 24 and 25 which ride in the grooves 26 and 27 of the key, guiding it until the end of the key abuts the sloping portion 31a from which point it is guided into the narrow portion 1.1 of the keyway. In its final position, the key will have part thereof lying in the narrow opening portion below the shutterillustrated n Fig. 4, while its tumbler setting portion Wlll rest, in the keyway 1 1 thus forming in effect, a key having parallel leg portions and operating in a keyway of the same shape.

It will be furthermore apparent that the operation of the bit 22, and the bits 24 and 25 cast integrally with the plug will so 11 nut the width of the keyway that the insertion of a tool for surreptitiously setting the tumblers will be very difficult, and operation of that tool will more than probably cause movement of the shutter into a plug locking position thus preventing the application of picking torque as has already been indicated. If a picking tool shaped like the key of Fig. 1 is utilized for picking the tumblers, it is quite obvious that any slight rotation of the plug from its position of Fig. 5, as Wlll necessarily be required to apply picking torque thereto, will lock the shutter 21 in positive offset keyway determining position, since the tongue 28 will be removed from opposite the slot 29. It will then be impossible to withdraw the key shaped picking tool, or to move it backwards and forwards as is necessary if it is to act individually on the tumblers as v is understood by those skilled in the art.

within the scope of the appended claims and which will readily occur to those skilled in the art.

We claim: v

1. In a lock, a key plug having a keyway, said keyway being formed of laterally off-set parallel portions, and an angular cominunieating passage connecting said portions.

2. In a lock, a key plug having a keyway, said keyway being formed for cooperation with a key having laterally offset parallel portions, and an angular communicating portion connecting said portions, :1 series of tumbler chambers in said plug having tumblers operable by contact with one of said key portions, and a shutter located in said keyway and operable by the other of said key portions.

3. In a lock, a key plug having a keyway, said keyway having an opening extension of relatively greater cross-section than the main keyway, a movable shutter covering the major portion of said enlarged opening, said lock being operable by a key adapted to enter said keyway through said opening, means on said shutter extending into the key, and means on said shutter adapted to lock the plug when improperly positioned by said 4. In a lock, a key plug having a keyway, an enlarged front opening leading to said keyway, an obstruction in said enlarged opening adapted to control the admission of a key into the keyway, and forming in effect, a plug keyway having laterally offset parallel portions, and an angular communicating passage connecting said portions.

5. In a lock, a key plug having a keyway, an enlarged front opening leading to said keyway, a movable obstruction in said enlarged opening adapted to control the admission of a proper key into the keyway and operable to prevent movement of said plug if improperly positioned, said obstruction forming said keyway and enlarged opening, in effect, into a keyway having offset portions and an angular communicating pas sage connecting said portions.

6. In a cylinder lock, a key plug having a keyway, an enlarged front opening leading to said keyway, a series q tumbler chambers leading into said keyw y, tumblers in said chambers, a shutter in t e enlarged opening of said keyway, means on said shutter adapted to lock the plug to the cylinder when actuated by an ordinary key or other instrument in the keyway, whereby said shutter acts to prevent effective operation of saidtumblers by any key other than one conforming to an opening into the keyway as defined by the shutter when it is in plug releasing position.

7. In a cylinder lock, 8. key plug. having a keyway, a series of tumbler chambers leading into said keyway, tumblers. in said chambers adapted to be set by a key in said keyway, an opening at the front of the plug leading into said keyway, a spring pressed shutter for said opening adapted to confine the key entrance said keyway being so as to form in combination withthe main keyway a composite keyway having portions of different configuration, and means on said shutter adapted to lock the plug to the cylinder when-the key does not conform to the keyway entrance as defined by said shutter. 8. In a cylinder lock, a die cast key plug, a portion of the head of said plug being cut away, an insert adapted to fit against said cut away portion to complete the head,-said insert and key plug forming at their junctions an opening for the operation of-a shutter, a key operated shutter in said opening, and an armor cap over said insert andfitting the head of the plug to hold the insert, the shutter, and the plug in assembled relation.

9. In a lock, a key plug having a keyway, formed of laterally offset parallel port-ions and an angular communicating passage connecting key set locking elements in each of said parallel portions.

10. In a lock, a key plug having a keyway, said keyway being in the form of a continuous passage having portions thereof in different vertical planes, and key operated locking elements in each of said portions.

11. In a cylinder lock, a key plug having a keyway, said keyway having a front communicating portlon leading into the main keyway, a serles of tumbler chambers leading into said main keyway, tumblers in said chambers, a shutter in said front-communicating portion, means on said shuttefadapted to lock the plug to the cylinder when actuated by an ordinary way, whereby said shutter acts to prevent effective operation of the tumblers y any key other than one conforming to an opening m .the front communicating portion as defined by the shutter when in its plug releasing position.

12. In a lock, a key plug having a keyway, .said keyway being formed of laterally offset parallel portions and an an eating passage connecting said portions, key set lockingelements lying in chambers communicating with each of said parallel porbeing cooperable with a key having also a pair of parallel portions and an ang lar portion connecting said parallel portion each of said parallel portions being adapted for cooperation with said key set locking elements. A

13. In a look, a key plug having a'keyway,

said keyway being in the form of a continuous passage having parallel portions in different vertical planes, key operated locking elements in said portions, said elements being cooperable with a key havin ortions and an angular portion connecting said parallel portions, each of said parallel key portions being adapted for cooperation with said key operated locking elements.

v 14. In a look, a key plug'having a keyway said portions, and

.into' said main keyway,

by an ordinary key key or other tool in the key lar communialso parallel and an enlarged front opening leading to said keyway, a. movable obstruction in said enlarged opening adapted to lock the plug against movement when improperly positioned and thereby adapted to control the admission of a proper key into the keyway, said obstruction forming said main keyway and enlarged opening, in effect, into a compositekeyway having ofi'set portions and an angular passage means whereby said shutter is movable in the locked position of the plug to permit entrance of a key or tool having the offset shape of said keyway, and means wherebysaid shutter is locked in its keyway determining position connecting said portions,

upon even slight rotation of said plug so as to said key or municating portion leading into the main keyway, a series of tumbler chambers leading tumblers in said chambers, a shutter in said front communicating portion, means on said shutter adapted to lock the plug to the cylinder when actuated or other tool in the keyway, said lock beingcooperable with a key having a pair of portions one of which conforms to the keyway as defined by said shutter, the other of said key portions being adapted to ride in the main keyway and having a contour cooperable with the tumblers communicatin with said main keyway.

16. In,a 100%, a key plug having a keyway and an enlarged front opening leading to said keyway, opening adapted to control the admissionot a. key into the keyway, and forming said main keyway and enlarged opening, in effect,

an obstruction in said enlarged said obstruction in said enlarged opening and a further, portion cooperable with said key set locking elements for operating said key plug.

17 In a look, a cylinder, a key plug in said cylinder having a main keyway and an enlarged front opening leading into said keyway, a key setvelement in said enlarged opening adapted to interlock with said cylinder except when in a predetermined releasing position, said element when in releasin position forming said plug keyway an enlarged opening in effect into ofi'set portions connected by an angular portion, said element being readily access to the main larged opening, position, locked in its offset keyway determining osition when said plug is rotated even slig tmovable to permit free keyway beyond the enwhen the plug is in locked said element being adapted to be ly for the application of picking torque thereto.

18. In a lock, a cylinder, 9. key plug in said cylinder having a main keyway and an enlarge'd front opening leading to said keyway, tumblers in said main keyway interloc ing with said cylinder, a movable key set element in said enlarged opening, a tongue on said element adapted to enter a slot in said cylinder to interlock said cylinder and plug except when said element is in predetermined releasing position, said element when in said releasing position forming said enlarged opening and said main keyway into a composite keyway having in eflectofi'set portions connected by an angular portion, said element being readily movable to permit access to said main keyway for operating the tumblers therein, said movement being op- 2 erable to force the tongue of said element into the cylinder slot, whereupon it prevents even such slight rotation of the plug as is required to apply picking torque thereto.

19. In a look, a cylinder, a key plug in said cylinder having a main keyway and an enlarg'ed front opening leading to said keyway, tumblers in said main keyway interlocking with said cylinder, a movable key set element iin said enlarged opening, a tongue on said element adapted to enter a slot in said cylinder to interlock said cylinder and plug except when said element is in predetermined releasing position,said element when in said releasing position forming said enlarged opening and said main keyway into a composite keyway having in effect oflset portions connected by an angular portion, whereby to permit operation of said plug tumblers by only a keyor tool conforming to the ofl's'et shape 40 required by said element, said element being movable'to permit entrance ofan oflset key or tool into sald composite keyway, the tongue of said element being removed from opposite its slot and acting to lock the element in its '45v keyway determining position upon even such slight rotation as will be permitted by the normal play between the tumblers and the cylinder.

Signed at Stamford, in the county of Fairfield, and State of (lofmecticutrthisfird day of December, 1931.

MAXWELL C. MAXWELL. FRANK E. THOMPSON. 

